The areas surrounding Rio de Janeiro and inhabited by the poorest are called favelas. They were built on the outskirts of the city as early as in the 19th century, when the unemployed war veterans and other representatives of the Brazilian poor settled there. In the vast, overcrowded slums very dense and primitive housing dominates - houses are built from cheap, partly recycled materials. Due to the high crime recorded in the slums, bullet holes are frequently seen on the facades of the buildings. Currently, the number of Brazilian favelas is estimated at about 750. The name "favela" refers to plants growing on the hills of Rio.